Visualizing and Animating R-trees and Spatial Operations in Spatial Databases on the Worldwide Web
František Brabec, Hanan Samet · 1998
The rationale behind the design of a JAVATM spatial index applet is described that enables users on the worldwide web to experiment with different variants of the R-tree. The applet is part of the VASCO system that contains JAVATM applets for a large set of hierarchical spatial data structures. The R-trees can be built using different splitting rules and include the R*-tree. The applet enables users to see in an animated manner how a number of basic spatial database search operations are executed for them. The spatial operations are spatial selection (i.e., a window or spatial range query) and a nearest neighbor query that enables ranking spatial objects in the order of their distance from a given query object. The results of the different splitting rules and the algorithms are visualized and animated in a consistent manner using the same primitives and colors so that the differences between the effects of the rules can be easily understood. The applet can be used to monitor the performance of spatial databases that use an R-tree spatial index as well as tune them by observing their behavior for different distributions of data. The applet can be found at http://www.cs.umd.edu/~hjs/rtrees/index.html.